This invention relates to magnetic suspension bearings, and more particularly to a magnetic suspension bearing for supporting a rotatable body and having two annular magnet assemblies which are axially aligned and magnetically poled so as to repel one another.
Known applications of magnetic bearings include the support of the rotor shaft of a watt-hour meter, the weight of which shaft and associated rotating bodies connected thereto being partially or completely compensated by magnetic fields. In the case of partial weight compensation, the pressure applied by the end of the shaft to a support bearing is reduced. In cases of complete weight compensation, the shaft is suspended in position by magnetic force. One known design of a magnetic suspension bearing for a vertical shaft contains a plurality of magnet systems arranged sequentially, one behind the other along the axis of rotation of the shaft. Each such magnet system has two coaxially arranged magnets which are magnetized radially, and poled so as to repel one another. Magnetic repulsion forces which are directed perpendicularly to the axis of rotation of the shaft constitute the forces which guide the shaft during rotation. The shaft is held in position so as not to move along an axial direction by separate stabilizing systems. One known stabilizing system utilizes the magnetic flux produced by a controllable electromagnet which acts upon a diamagnetic body connected to the shaft. Such a system is described in German Patent DE-AS No. 1 472 413.
In one known electromagnetic system which combines support and guidance functions, an armature bar which functions as the return path for an electromagnet, is disposed so as to be inclined with respect to the horizon. The resulting inclined position of the air gap produces a magnetic repulsion force which has components of force in the vertical and horizontal directions. In such an arrangement, the force component along the vertical direction serves as the holding force, and the force component along the horizontal direction serves as the guiding force. If the sum of all guiding forces is zero, the movable portion of the system is suspended within the stationary portion. Several electromagnets are arranged so as to be one behind the other along the direction of motion. The angle of inclination of the armature bars is chosen so that the individual electromagnets generate guiding forces alternatingly in opposite directions. Forces acting upon the moving body which are external to the system are compensated by corresponding changes in the guiding forces. Thus, this system, which is described in German Patent DE-AS No. 2 134 424, requires a sensitive and complex control system for the electromagnets.
It is, therefore, an object of this invention to provide a simple and improved magnetic suspension bearing.
It is a further object of this invention to provide a magnetic suspension bearing which combines magnetic support and guidance systems in such a manner that a rotatable body stably supported in axial and axially perpendicular directions without the need for additional stabilizing systems.